Blackfyre was a Valyrian sword that was brought to Westeros by Aegon I. After Aegon, all kings carried Blackfyre until Aegon IV gave the sword to his bastard son Daemon Blackfyre after the boy won a tournament. Supporters of Daemon later claimed that the gesture meant that Aegon intended for Daemon to succeed him as king. Partisans of Aegon's eldest legitimate son Daeron II claimed that the sword was just given to Daemon because it was of no use to Daeron, who was no warrior. After he had been legitimized, Daemon named his house (House Blackfyre) after the sword.